An autonomous vehicle may need to plan a safe trajectory for itself based on its environment. The problem may be referred to as motion planning, and the vehicle doing the planning may be referred to as the host vehicle. In order to avoid collision, the host vehicle may need to estimate the other vehicles' current position as well as predict their future intentions or trajectories. At the same time, the host vehicle may also be traveling at a high speed (e.g., 25-30 m/s) itself. Therefore, motion planning may require taking into account the complex environment as well as the goal of the host vehicle (e.g., the host vehicle may need to take the next highway exit).
Further, in addition to collision avoidance, there may be other desired objectives in the motion planning problem. For example, preferably passenger comfort should be taken into consideration when planning the motion of the host vehicle.